The present invention relates to transmitter circuitry for an ultrasound system, and, in particular, to circuitry for providing sub-beam formed transmit signals for an ultrasound system.
Referring to FIG. 1, a conventional ultrasound system includes a processor/controller 10 and analog front end (AFE) 20, as well as a user interface (not shown), such as a video display and computer keyboard and mouse. Included within the processor/controller 10 is a digital beam former 12 which provide multiple digital transmit data signals 13 defining the transmitted beam profile, and receives, in return, multiple digital receive data signals 33 representing the received energy profile. Any desired beam forming is performed within the beam former circuitry 12.
The transmission path of the AFE 20 includes multiple channels of digital-to-analog conversion (DAC) circuitry 22 and multiple transducer amplifier driver circuits 24. The transmit data signals 13 are converted to corresponding analog signals 23 for driving the driver circuits 24. Each of the resulting driver output signals 25 drives a respective transducer within the transducer array 28, and is conveyed via a transmit/receive switch 26, in accordance with well-known principles.
In accordance with further well known principles, reflected ultrasound energy received by the transducer array 28 is converted to corresponding analog electrical signals 27 which are conveyed via the transmit/receive switch 26 to respective time variable gain amplifier (TVGA) circuits 30. The resulting amplified signals 31 are converted by multiple channels of analog-to-digital conversion (ADC) circuitry 32 to produce the receive data signals 33.
Such ultrasound imaging systems operate in this manner to provide beam forming necessary for the desired image resolution and quality. As noted, the beam forming functions are typically implemented in the digital domain to achieve the desired flexibility and programmability. However, the power consumed by such digital domain circuitry has been increasing as speed and complexity of the processing increase. Such power consumption, and particularly any increases in power consumption, is particularly problematic as more systems are designed to be portable and operate under battery power. Additionally, as more complex transducer arrays are developed, the number of signals 13, 33 in the interface between the processor/controller 10 and AFE 20 have increased. Accordingly, it would be desirable to implement improved sub-beam forming so as to reduce power consumption and the number of signal connections between the processor/controller 10 and AFE 20.